This invention relates generally to the field of chemical production. More specifically, the invention relates to a method of producing a trisilane product.
Monosilane and other higher order silanes such as disilane and trisilane are useful as chemical precursors for the fabrication of integrated circuits. Typically, silanes are used as a starting material to produce a polycrystalline silicon, an epitaxial silicon, or an amorphous silicon film. Today, monosilane is most commonly used by the semiconductor industry, but it requires high process temperatures in order to decompose and create the desired film. As trisilane decomposes at lower temperatures than monosilane, trisilane allows the creation of silicon films at lower temperature process conditions and with greater overall film creation rates.
The synthesis of trisilane or other higher silanes has typically been accomplished through several methods. For instance, U.S. Pat. No. 6,858,196 teaches a method to obtain a higher silane by treating a lower silane with two electric discharge reactors which are connected in series. Monosilane is exposed to an electric discharge in a first reactor to create a product containing disilane. This product is then sent to a second reactor, and exposed to a second electric discharge to create a product containing trisilane. However, the plasma employed by this method can be unstable at high silane concentrations, making the method difficult to implement in large scale production.
U.S. Pat. No. 6,027,705 describes a method for obtaining a higher silane from a lower silane by conducting pyrolysis reactions in two reactors connected in series. However, this method uses monosilane as the starting point, and for trisilane it produces an extremely low reaction yield and production rate, making the method difficult to implement in large scale production.
Japanese Patent 02184513 teaches a method to create a higher silane through the dehydrogenation of monosilane in the presence of a specific catalyst. This method may lead to the formation of impurities like siloxanes, which may be very difficult to remove for the product. These chemical reactions also may have a very low yield and production rate.
Consequently, there exists a need for a method to produce a trisilane with a high yield and production rate, and with a low level of impurities.